Department of Otorhinolaryngology-Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA.
Department of Otorhinolaryngology-Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA.
Am J Otolaryngol. 2020 Nov-Dec;41(6):102647. doi: 10.1016/j.amjoto.2020.102647. Epub 2020 Jul 10.
To determine the severity and nature of audiometric threshold shifts for patients with pulsatile tinnitus (PT) due to sigmoid sinus wall anomalies (SSWA).
38 patients with SSWAs and available pre-operative audiograms were examined. Low- and high-frequency pure tone averages (LF-PTA, HF-PTA) were calculated. Audiometric data were compared between affected and unaffected ears, with the interaural difference (affected-unaffected PTA) representing the change in hearing due to PT. Additionally, post-operative change was examined in 14 patients with available data.
The average pre-operative air conduction (AC) LF-PTA was 17.04 dB on the affected side and 11.38 dB on the unaffected side (p < 0.001). The mean AC HF-PTA was significantly higher on the affected side as well (16.45 dB vs. 14.08 dB, p = 0.008). All shifts were sensorineural, with no significant air-bone gaps, and most subjects still had low-frequency thresholds in the normal range. Though the post-op change was not significant due to attrition, 5/14 patients (35.7%) had complete resolution of their pre-op interaural difference. A similar number developed a HF-PTA post-op threshold elevation in the surgical ear.
PT due to SSWAs causes a mean 6 dB low-frequency bone-conduction threshold elevation, and smaller high-frequency threshold shifts, due to masking. Patients with larger threshold shifts should have other potential causes of hearing loss explored.
Level IV.
确定由于乙状窦壁异常（SSWA）导致搏动性耳鸣（PT）患者的听阈偏移的严重程度和性质。
对 38 例 SSWA 患者和可获得的术前听力图进行了检查。计算了低频纯音平均值（LF-PTA）和高频纯音平均值（HF-PTA）。比较了患耳和非患耳的听力数据，听阈差异（患耳-非患耳 PTA）代表了 PT 引起的听力变化。此外，还检查了 14 例有可用数据的患者的术后变化。
术前空气传导（AC）LF-PTA 的平均值为患侧 17.04dB，非患侧 11.38dB（p<0.001）。患侧 AC HF-PTA 也明显更高（16.45dB 与 14.08dB，p=0.008）。所有的偏移都是感音神经性的，没有明显的气骨间隙，大多数患者低频阈值仍在正常范围内。尽管由于脱落，术后变化不显著，但 14 例患者中有 5 例（35.7%）完全消除了术前的听阈差异。同样数量的患者在手术耳中出现了高频阈值升高。
由于 SSWA 导致的 PT 导致平均 6dB 的低频骨导阈值升高，以及较小的高频阈值偏移，这是由于掩蔽效应所致。对于听阈偏移较大的患者，应探索其他潜在的听力损失原因。
IV 级。
